Case of the Month

Right upper quadrant pain and fever. The patient had undergone laparoscopic cholecystectomy some years earlier.

Diagnosis:   Dropped Gall Stones

Investigation

Left Image: A contrast enhanced MRI and MRCP of the liver demonstrated a stone in the distal bile duct (arrow) and mild proximal biliary dilation.

Middle and Right Images:  In addition, the scan showed numerous regions of perihepatic inflammation. Within many of these areas, there were round low signal structures consistent with gallstones (arrows).

Discussion

Laparoscopic cholecystectomy has become the accepted treatment for cholelithiasis. Bile duct injury (0.1 - 0.5% incidence),  gallbladder perforation (10-15%) and  'dropped stones' (10-13%) are among the more common complications. The incidence of abscess formation complicating 'dropped stones' is however only 0.3%. This may occur years after the original operation.

MRI demonstrates the 'dropped stones' as focal areas of low T1 and T2 signal. In the setting of abscess formation, the stone is seen within the abscess. Both CT and ultrasound may also on occasions demonstrate intra abdominal dropped stones.

MRI / MRCP of the liver is excellent at depicting bile duct injury and retained bile duct stones. 

Related References

Morrin MM, Kruskal JB, Hochman MG, Saldinger PF, Kane RA.  Radiologic Features of Complications Arising from Dropped Gallstones in Laparoscopic Cholecystectomy Patients. American Journal of Roentgenology 2000; 174:1441-45.

Sinha R, Verma R, Tyagi R. Extraluminal gallstone causing bowel obstruction. J Postgrad Med 2005;51:131-2.